Eddy current formation may be used in a variety of ways to adjust the speed of rotation of a member. Various apparatus exist, for example in abseiling, to control the descent of a climber or for example, in personal protective equipment scenarios to prevent an injury causing fall. Other applications that use eddy current generation are in controlling payout of line in trains, cable cars, zip line devices and roller coasters.
One art device is published as US2012/0055740. This device utilises a rotor assembly. The rotors themselves may be conductive or magnetic or may have conductive or magnetic members attached thereto. When a rotational force is applied, the rotors move outwards from a central axis via centrifugal force and into a magnetic (or conductive) field. As the rotors move through the field, eddy currents are generated, the strength of which is proportional to the speed of rotation.
As the speed of rotation reduces, the rotors are drawn back towards the axis of rotation via springs. This device is widely used however requires a number of moving parts. Another disadvantage is that, when the rotors move outwards and the field is generated, the magnetic field is not continuous around the circumference of the spin axis hence does not provide a continuous eddy current generation path.
As may be appreciated, reducing the number of parts in mechanical assemblies may be an advantage so as to reduce assembly cost. In addition, moving parts in mechanical assemblies generally require more maintenance and hence cost more. Minimising the number of moving parts may be advantageous. Maximising eddy current force generation may also be an advantage or at least it may be useful to provide the public with a choice.
Further aspects and advantages of the assembly and methods of use thereof will become apparent from the ensuing description that is given by way of example only.